Instructions
Model HF5B
Butternut presents the model HF5B BUTTERFLY compact beam antenna for the 10, 12, 15, 17, and 20
meter amateur bands! With elements only 12 ft 6 in (3.8 m) long and a turning radius under 7 ft (2.1 m), it
presents a low profile that allows it to be used in areas where other beam antennas would be restricted.
High-efficiency design and broad-band BUTTERFLY elements deliver performance expected only in
much larger designs.
SPECIFICATIONS
WINGSPAN:
BOOM LENGTH:
TURNING RADIUS: 6 ft 11 in (2.1 m)
VERTICAL SPREADERS: 6 ft (1.8 m)
SHIPPING WEIGHT: 22 lbs (10 kg)
FEED POINT IMPEDANCE:
VSWR AT RESONANCE: 1.5:1 or less on all bands
POWER RATING: 1200 W PEP
WIND LOADING: 3 ft2 (.3 m2)
WIND SURVIVAL:
BANDWIDTH:
GAIN: 3+ dBd 20 meters, up to 5 dBd other bands except 17 meters where
FRONT-TO-BACK:
FRONT-TO-SIDE:
TUNING SYSTEM: No traps; entire element length active on all bands; no tuner required.
MINIMUM RECOMMENDED
HEIGHT ABOVE GROUND: 30 ft (9.1 m)
12 ft 6 in (3.8 m)
6 ft (1.8 m)
Nominal 50 ohms. Includes RF connector for direct connection to any
length feed line terminated in PL-259
80 mph (129 kph)
VSWR 2:1 or less 1.5 MHz on 10 meters; entire band on 12, 15 and
17 meters; 200 kHz on 20 meters
antenna acts as rotary dipole.
Up to 20 dB
Up to 30 dB
Accepts up to 1 1/2 in (38.1 mm) mast. Light enough to be turned with a TV rotator.
831 North Central Avenue Wood Dale Illinois 60191-1219 Telephone 630@238@1183 Facsimile 630@238@1186 www.bencher.com
VI00159Z 080899-1-
BEFORE YOU START
WARNING: INSTALLATION OF THIS PRODUCT NEAR POWER LINES IS DANGEROUS.
FOR YOUR SAFETY FOLLOW THE INSTALLATION INSTRUCTIONS.
WARNING: AT NO TIME DURING ASSEMBLY, INSTALLATION, ADJUSTMENT, OR
OPERATION SHOULD ANY PART OF THIS PRODUCT BE ALLOWED TO COME INTO
CONTACT WITH ELECTRIC POWER LINES, NOR SHOULD THIS PRODUCT BE
INSTALLED IN SUCH A WAY THAT ANY PART OF IT MAY CONTACT POWER LINES
DURING NORMAL OPERATION OR IN THE EVENT OF STRUCTURAL FAILURE.
FAILURE TO EXERCISE EXTREME CARE IN THIS MATTER CAN RESULT IN
DAMAGE TO PROPERTY, PERSONAL INJURY, OR DEATH.
Before you start assembling the antenna, read through the instructions completely, paying special attention
to the pictorial diagrams. When you unpack the box, do so on a surface where you will not lose the small
parts. Check the parts against the PARTS LIST, identifying each part carefully.
NOTE: Check to see that all parts are present before beginning assembly.
NOTE: 3/4" screws unless directed to use other sizes.
INSTALLATION NOTES
CHOOSING AN INSTALLATION SITE: As with all directional antennas, care must be taken in the
choice of an installation site for your HF5B. Pick a place clear of power lines or other obstructions. The
HF5B should be mounted at least 30 ft (9.1 m) above the ground for proper operation. It should be able
to rotate without hitting anything. Finally, it should not be near any large masses of metal, like metal
roofing or siding. Plan your installation so that metallic guy wires are broken up with compression
insulators and no other antennas are nearby (like dipoles mounted right under the beam).
BALUNS: The sole purpose of the coaxial line "choke" balun shown in the instructions is to keep RF
current from flowing on the outside of the coaxial feed line. It does NOT transform impedances. This
form of balun has been featured in the ARRL Antenna Book for 40 years or more and it still works fine.
It also costs next to nothing. If, for some reason, you wish to use a commercially manufactured 1:1 balun
instead, make sure that it is installed BEFORE you do the "near ground" SWR adjustments on the driven
element. Most baluns will introduce odd bits of reactance into an antenna to which they're connected, and
that can throw off the tuning of a driven element that was adjusted with another balun in place or with no
balun at all.
MASTS AND GUYING: In order to avoid coupling between antenna elements and guy wires that can
detune the antenna it may be necessary to break up the guy wires with insulators. The typical metal "slipup" mast calls for a set of guys every ten feet or so, and that usually means a set close to the top of the
mast in order to steady the rotor and the antenna. If the separation between the antenna and the highest
set of guys is less that about 15 ft (4.6 m) it would be a good idea to use insulators on each of the
uppermost guys at intervals of 10 ft (3 m) or so. Place the first insulator on each guy AT THE MAST
OR TOWER, for that too is a conductor that can be coupled to the antenna by any horizontal or nearhorizontal guy wire connected to it. One or two insulators per guy wire should suffice because the HF5B
elements extend only a little more than 6 ft (1.8m) from the mast, and any coupling to the guy wire past
the second insulator will be negligible.
-2-
PARTS LIST
A. V00010 TUBE A — 72 in x 1 1/8 in (1.8 m x 28.6 mm) 4
V00011 TUBE A INSULATOR 2
B.
C. V00012 TUBE C — 72 in x 1/2 in (1.8 m x 12.7 mm) 4
D. V00014 WIRE 8
E. V00015 BRACKET END CLAMP E — 1 1/8 in x 3/16 in (28.6 mm x 4.8 mm) 4
F. V00018 BRACKET END CLAMP F — 3/8 in x 3/16 in (9.5 mm x 4.8 mm) 4
V00020 CLAMP SPACER G 4
G.
V00028 TUBE H — 36 in x 3/8 in (91.4 cm x 9.5 mm) 1
H.
I. V00029 TUBE I — 24 in x 3/8 in (61 cm x 9.5 mm) 1
V00030 TUBE J — 72 in x 3/8 in (1.8 m x 9.5 mm) 1
J.
V00031 STUB K U-SHAPED — 4 7/8 in (12.4 cm) long 1
K.
V00032 STUB L U-SHAPED — 7 1/4 in (18.4 cm) long 1
L.
-3-
PARTS LIST
M. V00033 STUB M U-SHAPED — 23 3/8 in (59.4 cm) long 1
N. V00034 STUB N U-SHAPED — 26 1/4 in (66.7 cm) long 1
V00040 CONNECTOR ASSEMBLY 1
0.
P. V00065 COIL P DRIVEN ELEMENT MATCHING 1
V00024 COIL CLAMP Q MATCHING — 1/4 in x 3/8 in (6.4 mm x 9.5 mm) 2
Q.
R. V00059 TUBE R — 72 in x 1 1/8 in (1.83 m x 28.6 mm) 1
S. V00067 PLATE BOOM TO ELEMENT 2
T. V00068 PLATE BOOM TO MAST 1
V00051 U-BOLT 1 in x 1 3/4 in (25.4 mm x 44.5 mm) 4
U.
V. V00052 U-BOLT 1 1/8 in x 2 in (28.6 mm x 50.8 mm) 10
W. V00053 U-BOLT 1 1/2 in x 2 3/4 in (38.1 mm x 69.9 mm) 2
V00054 BACKING CLAMP 1 1/8 in #308 (28.6 mm) 10
X.
-4-
PARTS LIST
Y. V00055 BACKING CLAMP 1 1/2 in #309 (38.1 mm) 2
V00057 LOCK WASHER 1/4 SPLIT RING 18-8 32
Z.
AA. V00056 NUT 1/4-20 HEX 18-8 32
BB. V00061 BUTTER-IT’S-NOT 1
CC. V00063 CAPACITOR CC 10/15M REFLECTOR 1
V00062 CAPACITOR EE 10/15/20M 3
EE.
FF. V00064 CAPACITOR FF 12/17M DRIVEN ELEMENT 2
V00044 CAPACITOR CLAMP HH — 1 1/8 in x 1 in (28.6 mm x 25.4 mm) 5
HH.
V00021 CAPACITOR CLAMP II — 5/8 in x 3/8 in (15.9 mm x 9.5 mm) 4
II.
V00026 CAPACITOR CLAMP JJ — 1 in x 3/8 in (25.4 mm x 9.5 mm) 1
JJ.
KK. V00022 CAPACITOR CLAMP KK — 3/16 in x 5/8 in (4.8 mm x 15.9 mm) 1
V00060 ROD LL 12M — 28 in x 3/16 in (71.1 cm x 4.8 mm) 1
LL.
-5-
PARTS LIST
MM. V00017 ROD CLAMP — 1 1/8 in x 3/16 in (28.6 mm x 4.8 mm) 1
V00045 ROD CLAMP NN — 1 1/8 in x 3/16 in (28.6 mm x 4.8 mm) 1
NN.
00. V00023 COIL/CAPACITOR CLAMP OO 17M — 1/4 in x 5/8in (6.4 mm x 15.9 mm) 1
PP. V00066 COIL PP 17M 1
QQ. V00025 COIL CLAMP QQ 17M — 1/4 in x 3/8 in (6.4 mm x 9.5 mm) 1
RR. V00050 KONNEKTOR-KOTE (1 X 8") .05
V00082 HARDWARE PACKAGE 1
SS.
BUTTERFLY™ ELEMENT ASSEMBLY
The Butterfly™ elements will be assembled first, tuned and then attached to the boom. The fully
assembled antenna may then be installed on the mast. Although the antenna may rest on the ground for a
short time, it’s best to have your mast and rotor in place before assembly. NOTE: Mast, rotor and
supporting structure are not included with the antenna.
1. Insert a 1 1/8" U-bolt (V) through backing clamp (X),
then through the center holes of spreader tube (C).
Slide the U-bolt over the end of element tube (A) that
does not have the hole in it. The backing clamp (X)
should now be sandwiched between element tube (A)
and spreader tube (C). Position the edge of backing
clamp (X) 3/4 in (19 mm) from the end of element
tube (A). Secure the assembly with two 1/4" lock
washers (Z) and two 1/4" hex nuts (AA) finger tight.
Place the “T” formed in step 1 on a flat surface with the threaded end of U-bolt (V) facing up. A couple
of wood blocks may be used under spreader tube (C) to provide support.
-6-
Insert one end of element tube insulator (B) into element tube (A) and align the holes. Insert a 1
2.
1/2" bolt, from the bottom, through element tube (A) and element tube insulator (B). Lay out two
spreader wires (D) and place one lug of each over the 1 1/2" bolt. Secure with a lock washer and
hex nut.
Insert a 3/4" bolt from the bottom of spreader tube (C). Place the remaining lug of one of the
3.
previously attached spreader wires (D) over the 3/4" bolt and secure with a lock washer and hex
nut.
Repeat step 3 for the remaining spreader wire (D) for the other end of spreader tube (C). Make a
4.
final alignment of tubes, U-bolt and spreader wires. Both spreader wires (D) should be on the same
side of element tube (A) as spreader tube (C). A slight bowing of spreader tube (C) should be
expected and will not hurt anything.
NOTE: BE SURE THAT THE ALIGNMENT OF ELEMENT TUBE (A) AND SPREADER TUBE
(C) IS CORRECT BEFORE PROCEEDING BECAUSE WHEN THE U-bolt IS FINALLY
TIGHTENED, ELEMENT TUBE (A) WILL DISTORT JUST ENOUGH TO FIX SPREADER TUBE
(C) INTO PLACE!
Tighten 1/4" hex nuts (AA) until they are flush with the end of U-bolt (V). Tighten the three hex
nuts securing spreader wires (D).
5. Assemble a second element tube (A), spreader tube (C), U-bolt (V) and spreader wires (D) as in
steps 1 through 4, attaching it to the other end of element tube insulator (B). This will form a
complete Butterfly™ element.
NOTE: MAKE SURE THE CAPPED ENDS OF SPREADER TUBE (C) ARE BOTH POINTING IN
THE SAME DIRECTION.
Repeat steps 1 through 5 to assemble a second Butterfly™ element.
6.
This completes the first part of the assembly process. Check your work to see that all parts are properly
aligned and all hardware is tight.
-7-
FOUR-WAY CLAMP ASSEMBLY
1. Using 3/4" bolt, attach plastic spacer (G) to bracket end clamp (E)
and secure with lock washer and hex nut.
Attach the other end of plastic spacer (G) to end clamp (F) with a
2.
3/4" bolt and secure with lock washer and hex nut as shown.
3. Repeat steps 1 through 3 for the remaining 3 clamp assemblies.
DRIVEN ELEMENT ASSEMBLY
When you install clamps in the following steps, apply a light coating of Butter-It’s-Not™ anti-seize/oxide
paste at the spot where the clamp attaches to the tubing. A paper towel or cotton swab may be used for
this purpose. Do not overdo it! Too much will cause problems later on.
Take either of the completed Butterfly™ elements and place it on a flat surface, using wood blocks
1.
for support at the ends. The threaded end of U-bolt (V) and spreader wire (D) should be facing
down.
Place a 4-way clamp around the left element tube (A) 4 1/2 in (11.4 cm) from element tube
2.
insulator (B). Secure with a 1" bolt, lock washer and hex nut.
3. Install tube (H) on the left side of the element as shown making sure that the end with the hole is
facing element tube insulator (B). Secure it with 3/4" bolt, lock washer and hex nut finger tight.
Position capacitor clamp (HH) 41 in (1 m) from 4-way clamp on the left element and secure it with
4.
1" bolt, lock washer and hex nut.
5. Position capacitor clamp (II) 30 in (76.2 cm) from 4-way clamp on tube (H) and secure it with 3/4"
bolt, lock washer and nut.
Install capacitor (EE) into the capacitor clamps installed above and secure it with 3/4" bolts, lock
6.
washers and hex nuts.
Using the chart below, position the u-shaped stub (M) on the 4-way clamp located on the left
7.
element and secure with 3/4" bolts, lock washers and hex nuts.
Band Segment (20 Meters) Spacing
Low (CW) Segment 18 3/4 in (47.6 cm)
Middle Segment 18 in (45.7 cm)
High (Phone) Segment 18 in (45.7 cm)
-8-
DRIVEN ELEMENT ASSEMBLY
8. Center 17M coil to cap clamp (OO) on the small tube of capacitor (FF) and secure with 3/4" bolt,
lock washer and hex nut.
Position capacitor clamp (JJ) 6 7/8 in (17.5 cm) from 17M coil to cap clamp (OO) on capacitor (FF)
9.
and secure with 1" bolt, lock washer and hex nut.
10. Install the above assembly on tube (H) as shown. Secure with 3/4" bolt, lock washer and hex nut.
11. Position 17M coil clamp (QQ) 16 1/2 (41.9 cm) from 17M coil to cap clamp (OO) on tube (H) and
secure with 3/4" bolt, lock washer and hex nut.
Install 17M coil (PP) between 17M coil clamp (QQ) and 17M coil to cap clamp (OO) and secure
12.
with 3/4" bolts, lock washers and hex nuts.
Place a second 4-way clamp around the right element tube (A). Using the chart below, position it
13.
from element tube insulator (B). Secure with a 1" bolt, lock washer and hex nut.
Band Segment (15 & 10 Meters) Spacing
Low (CW) Segment 9 3/8 in (23.8 cm)
Middle Segment 9 1/2 in (24.1 cm)
High (Phone) Segment 10 1/8 in (25.7 cm)
14. Install tube (I) on the right side of the element as shown. Secure it with 3/4" bolt, lock washer and
hex nut finger tight.
Center capacitor clamp (II) on the small tube of capacitor (EE) securing it with 3/4" bolt, lock
15.
washer and hex nut.
16. Attach capacitor clamp (HH) to capacitor (EE) and position it 7 in (17.8 cm) from capacitor clamp
(II). Secure it with 3/4" bolt, lock washer and hex nut.
Attach the above assembly to element tube (A) and position capacitor clamp (HH) 28 3/8 in (72.1
17.
cm) from the element tube insulator (B). Secure capacitor clamp (II) with 3/4" bolt, lock washer
and hex nut and capacitor clamp (HH) with 1" bolt, lock washer and hex nut.
18. Install u-shaped stub (L) on the 4-way clamp located on the right element and secure with 3/4" bolts,
lock washers and hex nuts.
Position 12M rod clamp (MM) on the right element tube (A) 3 1/4 in (8.3 cm) from element tube
19.
insulator (B) and secure with 3/4" bolt, lock washer and hex nut.
-9-
DRIVEN ELEMENT ASSEMBLY
20. Install 12M rod clamp (NN) to the right of 12M rod clamp (MM) and secure with 1" bolt, lock
washer and hex nut.
Position the 12M rod (LL) in 12M rod clamps (NN) and (MM), securing it with 3/4" bolts, lock
21.
washers and hex nuts.
22. Center capacitor clamp (KK) on the small tube of capacitor (FF) and secure with 3/4" bolt, lock
washer and hex nut.
Position capacitor clamp (HH) 9 1/2 in (24.1 cm) from capacitor clamp (KK) and secure with 3/4"
23.
bolt, lock washer and hex nut.
24. Attach the above assembly to 12M rod (LL) and position capacitor clamp (KK) 23 in (58.4 cm)
from 12M rod clamp (MM) and secure with 3/4" bolt, lock washer and hex nut.
Secure the other capacitor clamp (HH) on above assembly to element tube (A) with 1" bolt, lock
25.
washer and hex nut.
26. Install SO-239 connector (O) to tube (I) and secure it with 3/4" bolt, lock washer and hex nut.
Attach the free end of SO-239 connector (O) to tube (H) and secure it with 3/4" bolt, lock washer
and hex nut.
Install the matching coil clamps (Q), one on tube (I) and the other on tube (H) and secure both with
27.
3/4" bolts, lock washers and hex nuts.
NOTE: The gap between tube (H) and tube (I) is not critical but must be greater than 1".
28. Position driven element matching coil (P) between matching coil clamps (Q) and secure with 3/4"
bolts, lock washers and hex nuts.
This completes assembly of the driven element. Carefully check initial set-up dimensions making sure
everything is tight and set assembly aside.
-10-
-11-
Driven Element
REFLECTOR ELEMENT ASSEMBLY
1. Take the remaining Butterfly™ element and place it on a flat surface, using wood blocks for support
at the ends. The threaded end of U-bolt (V) and spreader wire (D) should be facing down.
Place a 4-way clamp around the left element tube (A) 5 1/2 in (14 cm) from element tube insulator
2.
(B). Secure with a 1" bolt, lock washer and hex nut.
3. Place the remaining 4-way clamp around the right element tube (A) 9 3/8 in (23.8 cm) from the
element tube insulator (B). Secure with a 1" bolt, lock washer and hex nut.
Attach tube (J) to the 4-way clamps and center over element tube insulator (B). Secure with 3/4"
4.
bolts, lock washers and hex nuts.
5. Install u-shaped stub (K) on the 4-way clamp located on the right element and secure with 3/4"
bolts, lock washers and hex nuts.
Using the chart below, position the u-shaped stub (N) on the 4-way clamp located on the left
6.
element and secure with 3/4" bolts, lock washers and hex nuts.
Band Segment (20 Meters) Spacing
Low (CW) Segment 24 3/4 in (62.9 cm)
Middle Segment 24 1/8 in (61.3 cm)
High (Phone) Segment 24 in (61 cm)
Center capacitor clamp (II) on the small tube of capacitor (EE) securing it with 3/4" bolt, lock
7.
washer and hex nut.
8. Attach capacitor clamp (HH) to capacitor (EE) and position it 10 in (25.4 cm) from capacitor clamp
(II). Secure it with 3/4" bolt, lock washer and hex nut.
Attach the above assembly to the left element tube “A” and position capacitor clamp (HH) 33 1/4 in
9.
(84.5 cm) from the 4-way clamp. Secure with 1" bolt, lock washer and hex nut.
10. Install capacitor clamp (II) over tube (J) and secure with 3/4" bolt, lock washer and hex nut.
11. Center capacitor clamp (II) on the small tube of capacitor (CC) securing it with 3/4" bolt, lock
washer and hex nut.
Attach capacitor clamp (HH) to capacitor (CC) and position it 5 in (12.7 cm) from capacitor clamp
12.
(II). Secure it with 3/4" bolt, lock washer and hex nut.
13. Using the chart below, position the above assembly element tube “A”. Secure with 1" bolt, lock
washer and hex nut.
Band Segment (15 & 10 Meters) Spacing
Low (CW) Segment 21 1/2 in (54.6 cm)
Middle Segment 21 1/8 in (53.7 cm)
High (Phone) Segment 21 in (53.3 cm)
Install capacitor clamp (II) over tube (J) and secure with 3/4" bolt, lock washer and hex nut.
14.
This completes assembly of the reflector element. Carefully check initial set-up dimensions making sure
everything is tight and set assembly aside.
-12-
-13-
Reflector
PRELIMINARY TUNING PROCEDURE
It is not always convenient or even possible to adjust the antenna at its full height above ground, so it is
suggested that the following "Near-Ground" tuning procedure be used. Even if further tunning is
contemplated once the antenna is raised to its full height, this procedure can greatly reduce the time one
must spend on the tower.
IMPORTANT: This procedure calls for the reflector element to be set aside during the adjustment of the
driven element. This means far enough away from the latter that it can't possibly exert any influence on
the driven element tuning. Any attempt to adjust the driven element close to the earth with the reflector
element in place will be a total waste of time and effort. Be sure not to place the driven element any
higher than seven feet off the ground because resonance on all bands will increase rapidly at much
greater heights. The SWR information below was gathered during examination of the driven element of
an HF5B that had been carefully (and tediously) adjusted at a height of 50 feet for lowest SWR consistent
with good F/B ratio.
The initial adjustment height of seven feet was chosen because it's not too hard to erect a simple and
temporary mast of that height for adjustment purposes and because the earth itself will take the place of
the reflector at that height, at least as far as driven-element resonance is concerned.
Remember that the height above ground and the mutual impedance between elements will have a lot to do
with antenna resonance, feed point impedance, SWR, and F/B. The advantage of this tuning procedure is
that if it's done properly you need not readjust the driven element once the antenna is raised to its final
position. If later adjustments are needed for better F/B ratio or SWR they can be confined to the
REFLECTOR element,
Be sure that the feed line approaches the driven element at right angles and that the driven element is well
away from other conductors. Use good quality coax in runs that are no longer than necessary. Long runs
of inexpensive RG-58 are to be avoided because the losses that go with it can produce abnormally broad
SWR curves that make it difficult to find the frequency of lowest SWR with any accuracy.
A final thought or two for the perfectionist: it is all but impossible to adjust a parasitic array so that the
maximum gain, maximum F/B rejection and lowest SWR will all occur at some particular frequency on a
given band. Finally, the dimensions for the driven element given are only approximate. They MAY
produce the desired resonances without further adjustment, but the likelihood is that they will not. The
HF5B element is reduced to about 41% of normal size on 20 meters, so slight errors in measurement and
the effect of nearby conductors will have greater effect on the tuning that with dipole element of more
normal size. The key is to adjust the driven element for lowest SWR (not necessarily 1:1) at one of the
frequencies given, and to set the reflector as described below.
For arrangement of components along the main tube of the driven element be guided by the pictorials, and
if you find that one component interferes with the free travel of another simply reset that clamp to the
other side of the obstruction and resume tuning. There are countless tuning combinations that will
produce the desired resonances, but you need to find only one. The 17 meter coil adjustment is more
critical than most, so adjustments must be made slowly and carefully.
The SWR bridge may be placed anywhere along the transmission line, but for the sake of convenience it
may be left near the transmitter and monitored while another person makes tuning adjustments out at the
driven element.
PRELIMINARY TUNING - DRIVEN ELEMENT
Please note that in the following steps you will be tuning only the driven element. Set the reflector
element aside during this procedure. Note too that you may be asked to tune the driven element for
resonance or lowest SWR at frequencies far removed from those on which you intend to operate. No
matter, for the resonances will change considerably when both elements are in place at their operating
height.
-14-
PRELIMINARY TUNING - DRIVEN ELEMENT
As always, the antenna should be clear of wires and other conductors to which it might become coupled.
1. Begin with the initial dimensions shown in the pictorial diagram. After these adjustments are
complete, set the reflector element aside and out of the way.
Position the driven element as shown below so that the plane of the element is approximately 7 ft
2.
(2.1 m). above the earth and roughly parallel to it.
3. Connect an SWR bridge and a calibrated signal source (or a transmitter) to the driven element,
making sure that the chassis is GROUNDED before plugging it into the power line in order to avoid
electrical shock.
Make SWR measurements over the 20 meter band and compare them to the SWR data listed
4.
below. If your measurements, particularly the point at which your SWR is lowest, do not resemble
those listed below it will be necessary to readjust the length of stub (M) until your lowest SWR
reading occurs at or very near that shown below. To move your lowest SWR to a higher frequency
shorten stub (M) by loosening the lower clamps of the 4-way assembly and pushing the open end of
stub (M) closer to the center of the element; to move your lowest SWR point to a lower frequency
increase the length of stub (M) by moving it in the opposite direction. Tighten the clamps and check
the SWR again, repeating this adjustment until your frequency of lowest SWR is the same as shown
below.
Band Segment (20 Meters) Tuning
Low (CW) Segment tune for lowest SWR at 14,140 kHz
Middle Segment tune for lowest SWR at 14,285 kHz
High (Phone) Segment tune for lowest SWR at 14,400 kHz
Your 20 meter adjustments should not be significantly affected by adjustments made for the other
5.
bands, so proceed to the 15/10 meter adjustment by noting your SWR readings over the 15 meter
band and compare them to the information given below. For 15 and 10 meters the 4-way assembly,
stub and all, on the other side of the element are moved toward the element center to lower the
frequency of the lowest SWR and away from the element center to raise the frequency of the
lowest SWR. Again, try to make your frequency of lowest SWR, coincide with that listed below.
Band Segment (15 Meters) Tuning
Low (CW) Segment tune for lowest SWR at 21,000 kHz
Middle Segment tune for lowest SWR at 21,100 kHz
High (Phone) Segment tune for lowest SWR at 21,225 kHz
Check your 10 meter SWR. This is determined by the previous 15 meter adjustment, but it should
6.
be reasonably close to the values given below. In any case, 10 meter tuning is quite broad, and your
frequency of lowest SWR should not differ significantly from that shown in the following chart.
Band Segment (10 Meters) Tuning
Low (CW) Segment tune for lowest SWR at 28,300 kHz
Middle Segment tune for lowest SWR at 28,475 kHz
High (Phone) Segment tune for lowest SWR at 28,725 kHz
-15-
PRELIMINARY TUNING - DRIVEN ELEMENT
7. Check SWR on 12 meters. Adjust for lowest SWR at 24.900 MHz. This adjustment involves
sliding double clamp (KK) along rod (LL) and capacitor (FF) to find the right amount of inductance
and to raise or lower 12 meter resonance. If more travel along rod (LL) is required, loosen the end
of double-clamp (HH) and slide capacitor (FF) and clamp (KK) as needed towards the element
center to raise the lowest SWR frequency, or away from the center to lower it.
Check the SWR on 17 meters. Tuning on this band is accomplished by varying the inductance of
8.
the coil by sliding double-clamp (00) along capacitor (FF) and the coil lead, toward the center of the
element to raise frequency and in the opposite direction to lower frequency. Adjust for lowest SWR
at 18.070 MHz. If more travel is needed along the coil lead for clamp (00), loosen the large clamp
on capacitor (FF), and move capacitor (FF) in or out as needed.
9. Re-check SWR on the other bands to make sure that nothing has changed, and readjust as required.
This completes the near-ground tuning procedure for the driven element.
PRELIMINARY TUNING - REFLECTOR
The reflector element does not usually require any special attention because there are fewer circuits to
adjust and because the capacitors am carefully selected with respect to tolerance. The preliminary
settings given in the pictorial should suffice in most cases. On the other hand, miniature antennas are
inherently much more critical with regard to adjustment for best F/B ratio and SWR. On all but 20 meters
the HF5B would have to be adjusted in place for best possible F/B over a particular band segment, but the
consensus is that even with full size arrays of only two elements such exertions are seldom warranted
because the possible improvement is not too great to begin with.
If however, one wishes to adjust the 20 meter reflector tuning for lowest SWR at some particular
frequency refer to the pictorial diagram of the reflector. If tubular capacitor (EE) is moved closer to the
center of the element, the reflector will resonate at a higher frequency and the lower of the two dips in
the 20 meter SWR pattern will similarly move higher in the band. If capacitor (EE) is moved out to the
end of the clement, the resonance will drop to a lower frequency as will the lower dip in the 20 meter
SWR pattern.
A change of approximately 1/2 inch in the position of capacitor (EE) will shift the 20 meter resonance
approximately 50 kHz. Remember, however, that the two dips on 20 meters should be remain from 150
to 200 kHz apart for reasonably good F/B rejection and that similar readjustment to the driven element
may then become necessary.
FINAL ASSEMBLY
In the final assembly, the two elements will be installed on boom tube (R).
Attach one boom to element plate (S) to each element using two 1" U-bolt (U), four 1/4" lock
1.
washer (Z) and four 1/4" hex nut (AA) per element. Do not use backing clamp (X) with the 1" Ubolt (U).
NOTE: BE SURE THAT BOOM TO ELEMENT PLATE (S) IS CENTERED ON THE ELEMENT
TUBE INSULATOR (B) AND DOES NOT SHORT TO EITHER ELEMENT TUBE (A)!
-16-
FINAL ASSEMBLY
2. Install boom to mast plate (T) on boom tube (R) using two 1 1/8" U-bolt (V), two 1-1/8" backing
clamp (X), four 1/4" lock washer (Z) and four 1/4" hex nut (AA).
3. Install two 1 1/2" U-bolt (W) on the opposite side of boom to mast plate (T) using two 1 1/2"
backing clamp, four 1/4" lock washer (Z) and four 1/4" hex nut (AA). Do not tighten until the
antenna is installed on the mast (not provided).
IMPORTANT! READ THE FOLLOWING STEP THROUGH TO THE END BEFORE
PROCEEDING!
4. Install the driven element on the end of boom tube (R) using two 1 1/8" U-bolt (V), two 1-1/8"
backing clamp (X), four 1/4" lock washer (Z) and four 1/4" hex nut (AA). Position the driven
element so the SO-239 connector (O) and u-shaped stub (L) are on the RIGHT side as viewed
from the center of the antenna.
5. Install the reflector element on the other end of boom tube (R) using two 1 1/8" U-bolt (V), two
1-1/8" backing clamp (X), four 1/4" lock washer (Z) and four 1/4" hex nut (AA). Position the
reflector element so the u-shaped stub (K) is on the RIGHT side as viewed from the center of the
antenna.
This completes the final assembly. Both elements should be on the boom, with the boom to mast plate (T)
mounted in the center. The edges of the boom to element plates (S) should be within 1/4" of the plastic
end caps on boom tube (R). The spreader tubes (C) and boom to mast plate (T) should be aligned 90° to
the ground.
-17-
INSTALLATION NOTES
The antenna may be installed as a unit atop the mast, or it may be installed one element at a time. Be
sure that the 10/15 meter side of each element is on your right as you face it from the tower. Either way
watch out for POWER LINES, guy wires, or other obstructions that may catch the antenna as it is going
up, causing damage, injury, or even death.
If you am using a small rotor, it must either be used with a thrust bearing or be mounted right under the
boom. A long mast above the rotor will result in damage to the rotor and antenna unless a thrust bearing
is used.
Guy wires must either be out of the immediate field of the antenna, nonconductive, or broken up by
compression insulators into non resonant lengths.
Do not hang dipoles below the beam! They will detune it.
The HF5B like any other 20 meter beam, must be AT LEAST 30 FT (9.1 M) above ground and "in the
clear" to work properly. If you do not heed this instruction, do not be surprised if there are tuning
problems.
CONNECTING THE FEED LINE
The HF5Bshould be fed with any good quality 50 ohm coaxial cable terminated in a PL-259 plug.
1.
Install the coax feedline as shown. Make a 10 turn
coil of coax 6 in (15.2 cm) in diameter and tape it to the
boom. This takes place of a balun and keeps RF off
of the feedline and tower. Then tape the feedline to
the boom and mast. Be sure that the coax is not free
to swing in the wind, putting stress on the coax
connector!
FROM THE AC MAINS TO AVOID SHOCK!
2. A 1:1 balun (not included) may be used at the
feed point but is not necessary. If you are not
planning to use a balun, construct an RF choke by
winding about 10 turns of the coax feed line in a 6
inch (15.2 cm) diameter coil, tape the coil
together, and hang it from the boom with tape or
wire. This device will help to keep RF off of the
feed line and tower.
Dress the coax along the boom, down and around
3.
the rotor in a loop loose enough to allow 360
degrees of rotation, and along the tower. Avoid
loose, dangling feed lines, as this can cause tuning
problems.
4. Use the small roll of coax sealer (PP) to cover the
junction of the PL-259 and the SO-239. Do not
place the sealer on the opposite side of the SO239 where the wire is soldered.
NOTE: THE COAX BRAID WILL BE AT GROUND
POTENTIAL IF THE ANTENNA IS INSTALLED
ON A GROUNDED SUPPORT! BEFORE
CONNECTING THE COAX TO YOUR
EQUIPMENT, DISCONNECT THE EQUIPMENT
FINAL TUNING
The HF5B is an efficient, short, high-Q circuit. As such, bandwidth tends to be a bit narrow on 20
-18-
FINAL TUNING
meters, where the 12 ft 6 in (3.8 m) elements represent only a small fraction of a wavelength. When
bandwidth is narrow, it is impossible "cookbook" the antenna by setting it according to the suggested
starting dimensions, then installing it on a push-up mast, where it will be unreachable for tuning! Be
prepared to do some tuning, even though you have set the antenna up per the instructions!
Note: Tuning adjustments for the driven element on 20 meters are made by changing the length of the 20
meter stub (M). Tuning for 15 and 10 meters involves moving the 4-way clamp assembly on the other
side of the element. Tuning on 17 and 12 meters is largely a matter of choosing the right length of rod or
coil lead where indicated, although slight compression or expansion of the 17 meter coil may be a more
convenient way to change circuit inductance on that band. All other driven clement dimensions should be
considered fixed for all bands and tuning conditions. Please read the following material carefully before
attempting to install the HF5B atop a tall mast where it cannot be reached for final adjustment.
Using low power, start with the 20 meter band, making an SWR curve. Make curves for 17, 15, 12, & 10
meters. If high SWR is encountered on all bands, suspect feed line or connector problems. Test the feed
line for shorts or opens.
Ideally, your SWR, curves should look like the ones you see in Figure 1, for 20, 15, and 10 meters.
Figure 1
The "dips" in the 20 meter curve should be 150-200 kHz apart. The higher frequency "dip" (on the right)
is from the driven element. The lower frequency dip is from the reflector. CHANGING ONE WILL
AFFECT THE OTHER!
EXPLANATION OF FIGURE 1
Please note that there were three sets of measurements given for 20 meter tuning depending on whether
you want the best SWR bandwidth and front-to-back ratio at the low, middle, or high end of the band. 15
and 10 meter tuning "track", and it is generally not possible to tune for absolute lowest SWR at the low
end of 10 meters without pulling the 15 meter resonance below 21 MHz. If, however, you wish to
operate over the low end of 10 meters with SWR no greater that 1.5 you should be able to do so and still
keep the minimum SWR above 21 MHz.
Pay special attention to the 20 meter SWR curve in Figure 1. This "double-dip" curve is characteristic of
tightly-coupled short elements and indicates that the parasitic reflector element is tuned only slightly below
the driven element on this band. The lower of the two dips represents reflector resonance, and the upper
dip (on the right) represents driven element resonance. The SWR curves in Figure 1 were obtained when
the antenna was mounted at a height of 50 ft (15.2 m) and in the clear; at heights below about 30 ft (9.1
m) you may see very different curves, especially if there are other conductors in the antenna’s field.
The 20 meter SWR curve in Figure 1 shows a difference in element tuning of about 160 kHz. Suppose
that the reflector element were adjusted for resonance at a slightly higher frequency or that the driven
element were adjusted for a slightly lower frequency. In such a case the two dips would tend to blend
into a single broad one. This arrangement is a common tuning error and will not yield very good F/B ratio.
If, on the other hand, the two dips are too far apart, one or even both dips may lie outside the band edges,
in which case both SWR and F/B will suffer. Luckily, forward gain is much less critical and should not
vary more than a decibel.
-19-
FINAL TUNING
F/B rejection will occur only over the LOWER, part of the SWR curve (the dip on the left), and will be
greatest when the difference between the dips is 150-200kHz. When the two dips are close together,
they tend to blend into a single broad dip, especially when the antenna is close to the ground. The
advantages of seeking the "double-dip" SWR curve is that its presence indicates a condition where the
antenna is tuned for reasonably good F/B rejection and that the operator may observe the effect of
adjustments made to the elements.
In any case, the proper procedure is to adjust for 20 meters first, then for 15 meters, 10 meters, 12 meters
and finally 17 meters. Remember, as before, it is assumed that you are viewing the element from the
tower, sighting along the boom from the mast. Tuning adjustments for 20 meters are made to the LEFT
side of each element while those for 15/10 meters are made on the RIGHT side. 15/10 meter tuning is
interlocked to some extent, but separate adjustments for 10 is usually not necessary as tuning is quite
broad on that band.
If the preliminary settings do not produce SWR curves on 10, 15, and 20 meters similar to those in Table
1, it may be necessary to modify those settings. Remember, however, that the evils of SWR greater that
1:1 have been grossly exaggerated in recent years and that time and effort spent in tedious adjustments to
achieve the lowest possible SWR on a given band will usually produce no noticeable improvement in one's
signal at a distant point! If the preliminary settings result in an SWR of, say 2:l or less over the intended
operating range, and if the transmitter is capable of delivering its rated power to the load represented by
the feed line and antenna system, adjustment for lower SWR will probably not be worth the extra time
and effort.
ROOFTOP INSTALLATIONS
Even though one has a high roof that seems suitable for the purpose of installing antennas, some cautions
should be observed. Wiring or other conductors in the attic or immediately under the roof covering can
become coupled to the antenna and affect its performance to a marked extent. Metal flashing under
shingles, rain gutters and other antennas and their feedlines, can all cause problems such as high SWR
and loss of F/B rejection, as can the beam's feed line if it can’t be run straight down from the antenna for
a quarter-wavelength or more before it has to run off in another direction. Unfortunately, some of these
problems can remain unseen or inaccessible, and there may be no cure for them short of relocating the
beam. If SWR changes significantly as the beam is rotated you should suspect some conductor or mass
of metal that you've overlooked.
USING HIGH POWER
The HF5B is rated at 1,200 watts PEP input power to the final amplifier. Exceeding this power level can
cause serious damage to the antenna. Avoid "pushing" this limit by a few hundred watts. To avoid
exceeding power limits, calculate INPUT power by multiplying AMPS times VOLTS on the amplifier's
meter, and adding feedthrough power for grounded-grid operation. THIS TOTAL SHOULD NOT BE
MORE THAN 1000 WATTS D.C.! DO NOT RELY ON A WATTMETER PLACED IN THE LINE
-20-
OPERATION
AFTER THE AMPLIFIER TO MEASURE POWER! IT IS EASY TO EXCEED LEGAL LIMITS
AND FAR EXCEED THE RATED LIMITS OF THE HF5B BY DOING SO.
The HF5B operates as a two element beam antenna on 10, 12, 15, and 20 meters. On 17 meters only the
driven element is active, and the element operates as a dipole. The direction of maximum signal on 10,
15, and 20 meters is off the driven element, with the second element acting as a reflector. On 12 meters
however, the second element is self-resonant above the driven element and acts as a director. Therefore,
maximum signal on 12 meters is off the back of the antenna. Because the second element is not in the
circuit on 17 meters, the driven element alone is active on that band, and no "front-to-back" will be
observed, although there will be noticeable "front-to-side" difference in signal strength.
There are no high impedance "traps" used to isolate sections of the elements in the HF5B design. As a
result, the entire element is active on all bands, except for the reflector, which is not used for 17 meter
operation. The U-shaped stubs and 3/8 inch tubes provide variable inductive reactance on their
respective bands, while the capacitors contribute fixed capacitive reactance on their respective bands.
The values of reactance are chosen to allow simultaneous resonances of the element on five bands
without the need for external tuners or mechanical switching. On 12 and 17 meters, the rod and coil take
the place of U-shaped stubs to provide the necessary inductive reactance. Impedance matching to the
short element on 20 meters is accomplished by placing a coil across the feed point. Fine tuning for the
best match is accomplished by compressing or expanding this coil slightly. To achieve maximum
bandwidth, the element "diameter" is increased by terminating the element in 6 foot spreaders and
connecting the spreads tips to the element’s center with the twisted wires.
Although the elements are only 12 feet 6 inches, efficiency is maintained by using the entire element
length and high-Q circuitry. Therefore, performance compared to a larger two-element beam is barely
compromised. Gain, front-to-back ratio, and front-to-side ratio are maintained in comparison to larger
beams, assuming the dual requirements of adequate operating height and a clear "field" are met. The
major compromises in a short antenna like the HF5B are a narrowed SWR bandwidth and a limited power
handling capacity.
CUSTOMER SERVICE
For service, please write to us including ALL PERTINENT INFORMATION. This means SWR
CURVES, COMPLETE DESCRIPTION OF YOUR INSTALLATION, AND DESCRIPTION OF
SYMPTOMS.
-21-
Top View
-22-
NOTES
-23-
LIMITED WARRANTY
Butternut Manufacturing Co. warrants on the terms hereof, to a Customer who has
purchased a Product from a Seller, for a period of one year from the date of the purchase,
that the Product was not Defective, but this warranty is void if the Product has been
subjected to improper or abnormal installation or usage, or a serial number on the Product
has been defaced or removed.
If a Customer believes that a Product is Defective, the customer may, within such
one-year period, return the entire product to Butternut at Butternut's factory, all shipping
charges pre-paid by the Customer. If the Product was Defective, Butternut will at its
option and expense repair or replace the Product and will at its expense return the repaired
or replaced Product to the customer, in a manner selected by Butternut, at the address
from which the Customer sent the Product to Butternut.
THE ABOVE WARRANTY AND REMEDY ARE EXCLUSIVE AND ARE IN LIEU OF
ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.
NO SELLER WILL BE LIABLE FOR ANY LOSS, INCONVENIENCE OR DAMAGE,
INCLUDING DIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES
RESULTING FROM THE USE OF OR INABILITY TO USE A PRODUCT, WHETHER THE
LIABILITY WOULD RESULT FROM BREACH OF WARRANTY OR UNDER ANY
OTHER LEGAL THEORY.
For instance, this warranty does not cover damage to or caused by an antenna (a) by
reason of the antenna acting as a lighting rod, (b) by reason of corrosion or strain from
exposure of an antenna to wind or weather, (c) from improper assembly, installation or use
of an antenna, or (d) from failure periodically to inspect and maintain an antenna and its
installation. The Customer is responsible to insure that installation and use of an antenna
complies with applicable laws (such as zoning laws) and regulations (such as
condominium regulations).
SOME LAWS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, AND
IF THESE LAWS APPLY, THEN ALL EXPRESS AND IMPLIED WARRANTIES ARE
LIMITED IN DURATION TO SUCH ONE-YEAR PERIOD. NO WARRANTIES OF ANY
KIND APPLY AFTER THAT PERIOD.
Such repair or replacement is the Customer's sole and exclusive remedy for a Defective
Product. Specifically, Butternut is not liable (to the Customer or otherwise) for (a) any
loss or damage arising in any way from a Product or from actual or anticipated sale, lease,
license or use of a Product, or involving any matter such as interruption of service, loss
of business or anticipated profits, or delay in receiving, repairing, replacing or returning a
Product, or (b) any incidental, indirect, special or consequential damages.
No other person (such as an employee, agent or dealer) is authorized to change this
warranty in any way, or to give any other warranties of any kind on behalf of Butternut.
This warranty gives a Customer specific legal rights, and a Customer may also have other
rights, which vary from state to state.
As used herein the Customer is the initial end-use purchaser of a Product from a Seller, a
Product is an antenna or accessory therefor manufactured by Butternut, a Product is
Defective if and only if the Product was not free of defects of material and workmanship
when manufactured, and a Seller is Butternut and any authorized Butternut dealer.
Butternut Manufacturing Co.
831 North Central Avenue Wood Dale Illinois 60191-1219
Telephone 630 238 1183 Facsimile 630 238 1186 http://www.bencher.com
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